Sofa



FIG. 1 is a front elevational view of a sofa in accordance with the present design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is an exploded perspective view thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a side elevational view thereof.

The broken lines in the drawings illustrate portions of the sofa that form no part of the claimed design. 

CLAIM The ornamental design for a sofa, as shown and described. 